feat(citation-verify): frontend "אימות פסיקה" tab in the decision editor (#154)

Frontend half of the citation-verification panel (backend in #323), as the agreed
third tab in /compose — matching the approved X17 mockup 24-citation-verification:

- lib/api/citation-verification.ts: hand-written types + useCitationVerification
  query + useVerifyCitation mutation (POST verify, invalidates the view).
- components/compose/citation-verification-panel.tsx: per legal argument →
  supporting corpus precedents with the cited_by authority chips (אומץ ×N /
  אובחן ×N), the exact supporting_quote, ✓ מאמת / ✗ לא רלוונטי verify actions, a
  per-citation chair-note field, and the per-issue 📡 radar (unlinked digests,
  pointer-only). Summary strip + INV-AH/INV-DIG1 reminders.
- compose page: third tab "אימות פסיקה" alongside עורך הבלוקים / עמדות וטענות.

No api:types regen needed (endpoints return assembled dicts; types hand-written
per the lib/api convention). tsc + eslint clean.

Invariants: INV-AH (writer cites only verified), INV-DIG1 (digest never cited),
G2 (consumes the one backend view). Visual matches the gate-approved mockup.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-ui/src/lib/api/citation-verification.ts

@@ -0,0 +1,103 @@
+/**
+ * Citation-verification domain (X11 Phase 2 / #154) — the compose "אימות פסיקה" tab.
+ *
+ * Per legal argument: in-corpus supporting precedents with the cumulative authority
+ * signal (cited_by — followed/distinguished), their verify state + chair note, and
+ * per-issue radar (unlinked digests). The chair verifies before the writer cites
+ * (INV-AH). Backed by GET/POST /api/cases/{n}/citation-verification[/verify].
+ */
+
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { apiRequest } from "./client";
+
+export type CitedBy = {
+  total: number;
+  positive: number;
+  negative: number;
+  unclassified: number;
+  by_treatment: Record<string, number>;
+};
+
+export type SupportingPrecedent = {
+  case_law_id: string;
+  case_number: string;
+  case_name: string;
+  quote: string;
+  score: number;
+  cited_by: CitedBy;
+  attached_id: string | null;
+  verified: boolean;
+  chair_note: string;
+};
+
+export type RadarLead = {
+  digest_id: string;
+  yomon_number?: string | number | null;
+  headline: string;
+  underlying_citation: string;
+  underlying_court: string;
+  score: number;
+  missing_precedent_id: string | null;
+  missing_precedent_status: string | null;
+  action: "new_lead" | "gap_open" | "fetched" | "available_link" | string;
+  matched_issues?: string[];
+};
+
+export type ArgumentBlock = {
+  argument_id: string;
+  title: string;
+  legal_topic: string;
+  priority: string;
+  party: string;
+  supporting: SupportingPrecedent[];
+  radar: RadarLead[];
+};
+
+export type CitationVerificationView = {
+  status: string;
+  case_number: string;
+  arguments: ArgumentBlock[];
+  summary: {
+    arguments_total: number;
+    arguments_with_support: number;
+    verified: number;
+    radar_leads: number;
+  };
+};
+
+export type VerifyCitationBody = {
+  argument_id: string;
+  case_law_id?: string;
+  quote?: string;
+  citation?: string;
+  chair_note?: string | null;
+  verified: boolean;
+  attached_id?: string;
+};
+
+export function useCitationVerification(caseNumber: string | undefined) {
+  return useQuery({
+    queryKey: ["citation-verification", caseNumber ?? ""],
+    queryFn: ({ signal }) =>
+      apiRequest<CitationVerificationView>(
+        `/api/cases/${caseNumber}/citation-verification`,
+        { signal },
+      ),
+    enabled: Boolean(caseNumber),
+    staleTime: 10_000,
+  });
+}
+
+export function useVerifyCitation(caseNumber: string | undefined) {
+  const qc = useQueryClient();
+  return useMutation({
+    mutationFn: (body: VerifyCitationBody) =>
+      apiRequest(`/api/cases/${caseNumber}/citation-verification/verify`, {
+        method: "POST",
+        body,
+      }),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ["citation-verification", caseNumber ?? ""] });
+    },
+  });
+}